This value identifies the IEEE-assigned organizationally
Unique Identifier (OUI) of the maker of this partner
DLSw. This information is obtained from a DLSw
capabilities exchange message received from the partner DLSw.
A string of zero length is returned before a Capabilities
Exchange message is received, or if one is never received.
If an implementation chooses to keep dlswTConnOperEntrys in
the `disconnected' state, this value should remain unchanged.